The Population Sciences Research Program (led by H. Anton-Culver and S. Neuhausen) is composed of three themes, Genetic Epidemiology (headed by S. Neuhausen), Prevention (headed by S. Lipkin), and Outreach and Cancer Control (headed by L. Wenzel). The Program is focused on investigating the continuum of cancer from normal to pre-malignant to malignant to metastatic disease. There are interactions and interplay among the three themes within cancer sites and across the continuum. The main objectives of the research are to build on current knowledge and to create new paradigms to understand: a) how cancers develop in susceptible populations;b) how to prevent cancer from developing;c) how cancers progress;and d) how to reduce morbidity and mortality from cancer. This research program is focused on organ-specific sites. Methodologies and approaches that are developed in one cancer are translated into other cancers. In the Genetic Epidemiology theme, breast cancer is a primary focus. There are five on-going studies to investigate genetic and lifestyle factors associated with risk of breast cancer. The identification of lifestyle and genetic factors that contribute to breast cancer risk is crucial to design both preventative and therapeutic strategies and to identify at risk individuals, in order to reduce the incidence of and death from this disease. In the Prevention theme, the focus is on chemoprevention. One of the most successful chemoprevention trials for secondary prevention of colorectal cancer is the randomized phase III study of Sulindac plus Difluoromethylornithine (DFMO) in Reducing Recurrent Colorectal Adenomas. Overall a highly significant reduction of 70% of all adenomas was achieved in those receiving DFMO/Sulindac (P<0.001). Advanced adenomas were reduced by 90% (P=0.001). In the Outreach and Cancer Control theme, a major focus is cervical cancer disease processes at the phase between susceptibility and pre-malignancy and after suspicion of a pre-malignancy in a high risk group of Hispanic women. Factors that influence survivorship after the malignancy has been treated are being identified to aid in cancer control and potentially prevent metastatic disease. Future emphases of the Population Sciences Program include quantitative assessment of factors that affect cancer etiology, progression and outcome to generate clues for cancer prevention targets. We will continue to focus on health disparities as they modify risk and outcome of cancer. The PS Program has 13 Members, representing four Departments and two Schools, and has $3,031,090 in direct cancer-related peer-reviewed funding, 11 projects of which are funded by NCI for a direct total of $2,382,560. In 2007, Members published a total of 60 publications with 45 of those being cancer-related of which 36% were inter- and 33% were intra-related.